Ski Builders Forum

Richuk wrote:Vinman, G-flex is expensive.

I was going to ask about using G-flex on gluing sidewall and edges.
Looks like good product for the job. Why not use it?
As far price. It a little bit more money compared to gorilla glue but definitely cheaper per Oz compare to loctite superglue

Bloefeld wrote: Upon reflection I think that abrading the plastic and then flaming will just give you little chunks of carbon that will break off from the plastic and decrease adhesion. So the alcohol wipe makes sense and clearly gives better bonding.

Smooth UHMWPE would not hold well IMHO. the abrading is necessary. The a
Alcohol wipe may help. Might have to test this for myself before using it tHough. The current consensus around here is no solvents on the plastic due to the possibility of residue creating a poor bond and delam. I have a buddy in the industry I'll ask him what they do.

Vinman wrote:

Bloefeld wrote: Upon reflection I think that abrading the plastic and then flaming will just give you little chunks of carbon that will break off from the plastic and decrease adhesion. So the alcohol wipe makes sense and clearly gives better bonding.

Smooth UHMWPE would not hold well IMHO. the abrading is necessary. The a
Alcohol wipe may help. Might have to test this for myself before using it tHough. The current consensus around here is no solvents on the plastic due to the possibility of residue creating a poor bond and delam. I have a buddy in the industry I'll ask him what they do.

no. The solvent destroys the flame treatment. Cheap Acetone leaves a residue. If the PE is really dirt clean it. MEK, Denatured alcohol. Isopropyl. Fast evaporative solvents are fine but you HAVE to re flame.

FYI, uwmwpe is suggested abrasion at 80-100 grit.

Coarser grit creates a weaker bond by overabraiding and leaving the surface too rough and can break away at bond.
Whatever you can do to get a similar surface to what crown provides stock as an abraded surface would be ideal.
I run them on my wet grinder and clean and flame prior to layup.

Nice MM. I did not know this about corse grit abrading. Thanks. I'll keep it to 80 grit from now on. This info should be in the bonding thread...

so i could just buy regular untreated uhmwpe, wipe it down with alcohol and flame treat it and it would bond better than the abraded stuff we get from isosport/crown/etc ? (given the wiping and flame treating is done properly)

YMMV. But I dont think so.
Every shop I have been to that laminates plastics has some level of abrasion and not smooth.

MR - I haven't used it. I made enquiries a while back, but then I was told about the press method. Given that I am using ski epoxy, I am assuming they designed it with these challenges in mind.

Given how critical the bondline between the core and sidewall to the failure of the planer process, I would jump on Tony's offer.

Grit levels for base material I have seen quote 120 grit. One problem is that grading is inconsistent within the paper industry. There is a research paper out there where they show a huge divergence according to brand - as seen under a scanning microscope. I think Norton came up well (from memory), whatever, it is probably worth saying that if you find a brand (AL oxide) and it works, stay with it.

ha, it just dawned on me why the poly-u failed on the last ski. My BTSR was zero!

Ha! Easily rectified!

Resurrecting this thread. After a long hiatus from experimenting I have
another experiment I hope to be performing this week. Waiting for some
9.4oz Uni Carbon Fiber to arrive. I'll create a similar layup using CF this time.
I may also make a layup of FG and CF and test them like I did for the other
test samples.

I will not be using poly-u glue this time around. I had some good results
using poly-u glue and raced on the poly-u ski all last winter. But I also had a
problem on another ski where the poly-u glue did not cure 100% before I
took it out of the press. The ski was dead flat out of the press, but then the
uncured poly-u glue started to expand under the base and tiny bumps
formed. I was seriously bummed out. Anyway I haven't totally shelved the
use of poly-u just yet.

The new Capita Snowboards homepage also says that it's a polyurethane resin they're using to build their boards at the Elan factory. I'd love to know who makes that stuff and how it performs.